Why Are Plants Green Instead of Black?

Plants are green because they use sunlight to make food, and green is the color that helps them do this best.

Imagine you're playing outside on a sunny day, and you wear sunglasses that block out all the colors except green. That’s kind of like what happens to plants, they let most of the light pass through, but they catch the red and blue parts to make their food. The green part gets left over, so it reflects back at us, making the plant look green.

If plants were black, that would mean they’re absorbing all the sunlight, like a dark towel soaking up every drop of water. But just because something absorbs all the light doesn’t mean it’s good at using it. Think about wearing a black shirt on a hot day, you get super warm, but your shirt isn’t doing anything special with that heat.

Plants don’t need to absorb all the sunlight. They only need what they can use to make food, and green is just right for that job. So instead of being black, plants stay green, like a perfect filter for sunlight.